Long-term outcomes of adolescent idiopathic scoliosis: Natural history of untreated, braced, surgically treated patients in adult life

Abstract

To evaluate the long-term clinical, functional, psychosocial, and radiographic outcomes of untreated, braced, and surgically treated adolescent idiopathic scoliosis (AIS) into adulthood. A narrative synthesis of key studies - including prospective cohorts, retrospective analyses, systematic reviews, and patient-reported outcome measure-based investigations - was conducted. Data were organized into three domains: The natural history of untreated AIS, outcomes of bracing, and surgical treatment. Comparative analyses were performed across functional capacity, curve progression, health-related quality of life, patient satisfaction, and complication rates. Untreated AIS with curves < 50° often follows a benign course, with minimal functional limitation, preserved health-related quality of life, and no increase in mortality. However, curves ≥ 50° are associated with progressive deformity, cosmetic dissatisfaction, and potential pulmonary compromise. Bracing is effective in halting progression in skeletally immature patients, particularly when in-brace correction exceeds 50% and daily compliance exceeds 18 hours. Surgically treated patients report the highest long-term satisfaction, particularly in self-image and cosmetic outcomes, though fusion may result in some loss of spinal mobility. Delaying surgery into adulthood increases the risks of operative morbidity, extensive fusion levels, and reoperation. AIS is a heterogeneous condition requiring individualized, evidence-informed care. Observation is appropriate for non-progressive, moderate curves; bracing remains a first-line intervention for growing patients with moderate deformity; and surgery is indicated for progressive or severe curves, with favorable long-term outcomes when timed appropriately. Patient-reported outcomes, psychosocial considerations, and shared decision-making should be integral to treatment planning. Continued prospective research and standardization of bracing and surgical protocols are essential to optimize outcomes across the lifespan.

Keywords: Adolescent idiopathic scoliosis; Long-term outcomes; Bracing; Spinal fusion; Natural history; Patient-reported outcomes; Quality of life

Core Tip: Adolescent idiopathic scoliosis is a heterogeneous condition with outcomes extending into adult life. This review synthesizes four decades of evidence on untreated, braced, and surgically treated adolescent idiopathic scoliosis. Curves < 50° generally follow a benign adult course, whereas progressive deformity may impair self-image and function. Timely bracing and appropriately indicated surgery provide favorable long-term functional and psychosocial outcomes, highlighting the importance of individualized care and shared decision-making.